Biofeedback of real-time functional magnetic resonance imaging (rt-fMRI) data is a new technique in which the activity in a specific region of a subject's brain is provided as a feedback signal to the subject. The subject can experiment with different cognitive strategies to identify those that are effective in influencing brain activty in the region of interest. By practicing those strategies and monitoring their success, subjects can train themselves to control the target brain region. The proposed research project applies this technique to obsessive-compulsive disorder (OCD). More specifically, the project examines whether biofeedback of rt-fMRI data can enable individuals with OCD to develop control over activity in a region of their orbitofrontal cortex involved in symptom anxiety and thereby reduce their obsessive-compulsive symptoms. If so, this new technique may yield a low-risk, non-invasive clinical intervention for OCD. In addition, patterns of resting state functional connectivty between brain areas will be examined before and after biofeedback to determine how intrinsic brain dynamics are altered by the intervention, and how those alterations relate to changes in clinical symptoms. This will inform our understanding of the network dynamics underlying obsessive-compulsive symptoms. Although this research project is focused on developing a protocol specifically for treating and studying OCD, the methodology has great promise as both a treatment intervention and a research tool for a broad range of neuropsychiatric disorders.